There are many utilities for synchronizing folders via SFTP on Linux, but most of them are visual (eg Filezilla). There are not so many good utilities for the command line. For example, there is the sftp utility, but it is not very convenient, you cannot synchronize the whole folder recursively using it. Therefore, here we will look at lftp, which works from the command line and allows you to do a lot of operations using the SFTP protocol.
Installing lftp is very easy. For example, for Ubuntu:
apt-get install -y lftp;
After installation, you can immediately use it. The logic of the program is such that we can write a script and run it. There at script will be a connection to the SFTP server and some action that we need. For example, let’s say we need to copy the entire folder from the local computer to the server via SFTP. Example of a command:
lftp sftp://username:email@example.com -p 22 -e 'set sftp:connect-program "ssh -o StrictHostKeyChecking=no -a -x -i /home/.ssh/yourkey.key"; mirror -eRv /var/from-folder/ /var/to-folder; quit;'
Here is a command to connect to an SFTP server using an ssh key. Commands for lftp are listed in the -e option separated by semicolons. After the connection, the contents of the /var/from-folder/ folder are copied from the local computer to the /var/to-folder folder on the server recursively (with all subfolders).
Note that to login with a key, the sftp:connect-program variable is first set, which contains the ssh connection command and path to the key. The StrictHostKeyChecking option has been added so that the server’s fingerprint will not be checked, it is assumed that we trust it.
Even if we use a key, the password must be specified: username:password. If not specified, lftp will ask for a password. If we authorize by key, we need to specify any string as a password.